NASA's Hubble Space Telescope has probed the bright core of Comet 17P/Holmes, which, to the delight of sky watchers, mysteriously brightened by nearly a million fold in a 24-hour period beginning Oct. 23, 2007. Astronomers used Hubble's powerful resolution to study Comet Holmes' core for clues about how the comet brightened. The orbiting observatory's Wide Field Planetary Camera 2 (WFPC2) monitored the comet for several days, snapping images on Oct. 29, Oct. 31, and Nov. 4. Hubble's crisp "eye" can see objects as small as 54 kilometres across, providing the sharpest view yet of the source of the spectacular brightening.
Title: Comet P/Holmes, 1892III - A case of duplicity? Authors: Whipple, F. L.
An analysis of observations of comet P/Holmes 1892III's two 8-10 mag bursts indicates that these phenomena are consistent with the grazing encounter of a small satellite with the nucleus on November 4.6, 1892, and the final encounter on January 16.3, 1893. While after the first burst the total magnitude fell less than 2 mag from November 7 to 30, the fading was much more rapid after the second burst. It is suggested that the grazing encounter distributed a volume of large chunks in the neighbourhood of the nucleus, maintaining activity for weeks.
The path of Comet P/17 Holmes through the constellation Perseus for the period between November 10th to December 7th, 1007. (Daily intervals at midnight).
Solutions to chess problems and astronomical dilemmas
Recently John Nunn, retired world-class grandmaster, won the 31st World Championship for problem solvers. In our report we showed you some sample problems today we provide the solutions. John is also an amateur astronomer, who owns a 10-inch Schmidt-Cassegrain telescope. He sent us some pictures he took with a normal digital camera. They include the moon and an exploding comet. Read more
Did a collision cause comet's mysterious outburst? Comet 17P/Holmes has certainly given sky-watchers - backyard and professional astronomers alike - a thrilling chance to see a cometary outburst on a grand scale. After we posted my story about on-going speculation about what could have caused this outburst (and the one 115 years ago), many readers posted comments related to two questions: Could this have been triggered by a collision with an object in the main asteroid belt? And why can't we see more of a tail on this comet? Michael Mumma at the Goddard Centre for Astrobiology says such a collision in the asteroid belt is theoretically conceivable. He noted that comet guru Fred Whipple suggested that a collision with a small asteroid could have provided the right amount of energy to produce the ejecta and brightening observed in the comet's 1892 flare-up. But Mumma himself thinks it would be "very surprising" if a collision were the cause of the outburst. He says part of the difficulty in weighing this possibility is that it's very hard to estimate how many small boulders are in the asteroid belt. These tiny objects on the order of one-metre across are beyond the detection limits of telescopes. Brian Marsden, former director of the International Astronomical Union's Minor Planet Centre, says plainly that he doesn't believe this to be a viable explanation for the outburst. He says it's hard to believe that this comet, among all those that pass through the asteroid belt, has been struck twice by objects in the belt once in 1892 and again this year.
University of Tennessee Astronomy Director Paul Lewis in Knoxville is drawing students to the roof of the physics building for special viewings of the comet. He says this is truly a celestial surprise and a once-in-a-lifetime event to witness. Experts aren't sure how long the comet's show will last, but they estimate it could be weeks if not months. Read more
Indiana University's Kirkwood Observatory will be extending its viewing hours to 11 p.m. on Wednesday, Nov. 7, to allow viewing of the Comet Holmes. The comet used to be too faint to see with the Observatory's telescope. However, between Oct. 23 and 24, the comet suddenly brightened by nearly one million times, making it as bright as Big Dipper stars. The comet has not been this bright since its discovery in 1892 and will slowly fade over the coming weeks.